Concrete block forming apparatus



Oct. 25, 1960 L. ZMANIA ETAL CONCRETE BLOCK FORMING APPARATUS Original Filed June 20, 1956 I 4 Sheets-Sheet 1 N E m m T N 6 0 m I M. T 2 VZC T I A "a o w v 4 new 9 1.0, A M w Y 5 7 B I 2 9 3 a h P 1 2 H H I H HWI U 4 h rl r n M i 8 1 a. lllqJl l; 2 7 .1 3 n. K 3 3a x Z A 6 58 5 r? a a Oct.-25, 1960 L. ZMANIA ETAL 2,957,221

CONCRETE BLOCK FORMING APPARATUS Original Filed June 20, 1956 4 Sheets-Sheet 2 ATTORNEY Oct. 25, 1960 L. ZMANIA ETAL 2,957,221

CONCRETE BLOCK FORMING APPARATUS Original Filed June 20, 1956 4 Sheets-Sheet 3 Oct. 25, 1960 L. ZMANIA ETAL 4 Sheets-Sheet 4 Feed 2 L Mam Dru/e L K I Feed Coni'ro\ 5 W2 Mahar- 5W3 f 0c 0000mm FZ" a 70 H H C2 Pm Cu-cuii as: [2 70 p 70 15.1; H FDT l i l 62-1.: mii swdd,

" f/yam HTTORIIEY United States Patent- CONCRETE BLOCK FORMING APPARATUS Leo Zmania, 6925 111th Place, Worth, 111., and Marvin C. Onsen, Box 1836, Rte. 1, Albuquerque, N. Mex.

Continuation of application 'Ser. No. 592,665, June 20, 1956. This application Mar. 2, 1960, Ser. No. 12,376

14 Claims. (Cl. 25-41) This invention relates generally to block manufacturing and more particularly is concerned with improved means for manufacturing concrete building blocks which are uniform in size and density, this application being a continuation in part of copending application Serial No. 470,661, filed November 23, 1954, and a continuation of copending application Serial No. 592,665, filed June 20, 1956, and now abandoned.

A principal object of the present invention is to provide a concrete building block machine with improved height and density control means which functions automatically and without any necessity for stopping the machine.

' Another object of the present invention is to provide such a device which can adjust for each block forming cycle and which is operative to reduce a concrete charge in a mold of predetermined cross sectional area to an uncompacted height dependent upon the condition of the concrete charge from which the last block was made.

Still another object of the present invention is to provide such a device which adjusts as aforementioned to effectively control the operating level of means for wiping across the top of the mold to afford an uncompacted charge of concrete the height of which bears a critical relation to the condition of the concrete charge from which the last block was made.

And a further object of the present invention is to provide a concrete building block machine which normally is operative to terminate the compacting operation when the concrete in the mold is finally reduced to a predetermined height, without regard to the point in the block making cycle when the concrete may be reduced to such height.

And still another object of the present invention is to provide such a device which is exceedingly simple in design and construction and which is comparatively simple and inexpensive to manufacture.

Other objects and advantages of the present invention will appear more fully hereinafter, it being understood that said invention consists substantially in the combination, construction, location and general arrangement of parts, all as described in detail in the following specification, as shown in the accompanying drawings and as fully pointed out in the appended claims.

In the accompanying drawings:

Figure 1 is a fragmentary view looking at the righthand side of a block forming machine constructed in accordance with and embodying the principles of the present invention, improved portions of the machine being shown in full lines and old structure being shown in broken lines;

Figure 2 is a plan view of the improvements shown in Figure 1;

Figure 3 is an enlarged front view of the improvements shown in Figure 1;

Figure 4 is an enlarged view of the area encircled in Figure 2;

Figure 5 is a vertical section taken on line 5-5 of Figure 4;

Figure 6 is a vertical longitudinal section taken through the front end of the block forming machine, the feed box being shown in an elevated position;

Figure 7 is an elevation looking at the left-hand side of the block making machine; and

Figure 8 is an elementary wiring diagram schematically showing the electric circuit for controlling the opera-.- tion of the block making machine.

The feed box assembly of the present invention includes a conventional feed box, indicated generally by the numeral 10, and a track or feed box mounting subassembly, indicated generally by the numeral 11. This subassernbly is provided with a pair of laterally spaced support bars 12-42 that extend horizontally fore and aft of the machine, the opposite end portions of each support bar 12 being vertically offset, as shown. Between the fore end portions of these support bars are a pair of laterally spaced tracks 13-13 that extend horizontally fore and aft of the machine parallel to one another, each in spaced relation to the associated support bar. Disposed in underlying spaced relation to the aft end portions of the tracks 13-13 and fixed to the same through the medium of a pair of spacer elements 14-14 is the fore end of a horizontally disposed apron plate 15 that extends rearwardly to vertically extending support bar portions designated 16-16. Suitably secured to the underside of the apron plate 15, at the fore end thereof, is a stiffener angle 17. The tracks 13-13 are each seated upon a clip angle 18 that is fixed to the inner side of the associated support bar, and the aft end of the apron plate 15 is seated upon a pair of clip angles 19-19 that are fixed respectively to the inner sides of support bar portions 16-16.

Extending horizontally between the support bar 12-12 and secured to the aft end portions of the bars aforesaid is a cross beam 20, and mounted upon this beam, inter.- mediate the ends thereof, is a bracket 21 that carries a roller 22 which is freely rotatable about a horizontal axis extending transversely of the machine.

The fore end of the feed box 10 is provided with a pair of rollers 23-23 that respectively overlie the tracks 13-13, and the aft end of the feed box 10 is provided with a runner plate 24 that overlies the roller 22, in consequence of which the feed box 10 may be shifted fore and aft relative to the underlying track subassembly 1-1.

Extending horizontally across the machine, a short distance forwardly of the cross beam 20, is an axially fixed pivot shaft 25. The opposite end portions of this shaft project respectively through corresponding portions of the support bars 12-12, each terminating in a bearing 26 carried by the associated section of the main frame of the machine, designated 27, in consequence of which the feed box 10 and the track subassembly 11 may be rocked as a unit about the axis of the pivot shaft 25.

Fixed by their lower ends respectively to the fore ends of the support bars 12-12 are a pair of upright brackets 28-28 the upper ends of which suitably mount respectively a pair of coaxially related pins 29-29. A pair of links 30-30 extend upwardly parallel to one another respectively from the pins 29-29. The upper ends of the lines 30-30 are connected respectively to a second pair of coaxially related pins 31-31. On the righthand side of the machine, the opposite end portions of the pin 31 are journalled respectively in opposed portions of a pair of flat bar members 32 and 33 that are disposed in upright planes which extend longitudinally of the machine, and on the left-hand side of the machine, the opposite end portions of the pin 31 are journalled respectively in opposed portions of a pair of fiat bar members 34 and 35 that are disposed in upright planes which extend longitudinally of the machine. Each of these members 32 through 35 extends horizontally rearwardly from the pins 31--31 and is rigidly secured to a rock shaft 36 that extends horizontally across the top of the machine and which'has opposite end portions journalled respectively in a pair of bearings 37-37.

These bearings are mounted respectively upon a pair of suitable upright plates 3838 that have their lower end portions connected respectively to the opposed sides of a pair of beams 39'39 which extend horizontally parallel to one another rearwardly from the plates 38- 38. The aft end portions of the beams 3939 are anchored to'the main frame 27 of the machine through the medium of bolts 4040 and brackets 41-41, while intermediate portions of the beams 3939 are anchored to the main frame 27 of the machine through the medium of bolts 42-42 and brackets 43-43, in consequence of which the fore end portions of the beams 39 39'are cantilevered over the fore end of the machine.

- Extending horizontally across the top of the machine .end portions of the'beams 39-39. The beams 44-44 mount a drive unit 46 that has a drive shaft 47 which is adapted to turn a cam 48 about an axis that extends horizontally across the machine. The face of the cam engages a cam follower in the form :of a roller 49. The latter is carried by a flat bar member 50 that extends rearwardly and'downwardly from the rock shaft 36 and which is rigidly secured to the latter, and by a similarly extending portion of the flat bar member 34.

The flat bar member 33 extends both forwardly and rearwardly from the rock shaft 36, the aft end portion thereof being fitted with a counterweight 51, and the fore end portion thereof being fitted with a depending hand lever 52. The opposite end portions of this lever 52 are horizontally offset, as shown, and the lower end portion thereof is sandwiched between a bracket plate 53 and a ratchetrplate 54. This ratchet plate is carried by the bracket plate, and the latter is secured to the main frame 27 of the machine by a plate 55. A pawl 56 that is pivotally mounted upon the hand lever 52 is adapted to operatively engage the teeth of the ratchet plate 54, and a graduated scale plate 57 mounted upon the outer side of the ratchet plate 54 is adapted to be read with the aid of an indicator 58 that is carried by the hand lever 52.

The fore end of the feed box assembly is carried by the links 3030, and the load on these links is substantially balanced by the counterweight 51. The shaft 36 normally is rocked by the cam 48 acting on the roller 49. When the cam 48 is oriented so that the roller 49 engages a low portion of the cam, the front of the feed box assembly is supported in one'of its lower posi tions, as in Figure 1, for example, and when the cam 48 is turned so that the roller 49 engages a higher portion of the cam, the feed box assembly is rocked as a unit about the axis of the pivot shaft 25, andthe front of the feed box assembly is elevated to a higher position, as in Figure 6, for example. When the cam 48 is oriented so that the roller 49 engages a low portion of the cam, the fore end of the feed box assembly may be moved vertically to a selected position by manually actuating the lever 52, the pawl 56 operatively engaged with the teeth of the underlying ratchet plate 54 automatically operating to secure the feed box assembly in'the posi- 4 directions. For preventing over-running of the drive unit, there is provided a spring loaded drag brake (not shown),

Referring particularly to Figure 3, on the left side of the machine, in plain view of the operator, is an instrument panel 63 that mounts an actual finish time indicator 64, a desired finish time indicator 65, a feed time? 66, a selector switch 67, and iaisef and lower push bumsns designated respectively 68 and 69. V

Refer-ring particularly to Figure 8, the electric .circuit for controlling the operation of the block making machine essentially includes a main drive motor MD that has a starter which is equipped with a coil designated M, and a feed control motor FCM that has a reversing starter which is equipped with an up coil and a down coil respectively designated U and D. The actual finish time indicator 64 is an elapse time indicator the coil of which is designated F11, and the desired finish time indicator 65 and the feed timer 66 are adjustable motor driven timers the coils of which are designated respec tively FT and PDT. Time delay relays for up correc= tion, to prevent hunting of the mechanism and for down correction are designated respectively TR1, TR2 and TR3. The height pins or determiners of the machine, designated 70, have associated therewith a relay HP and coils designated C1 and C2. 'Driven by and in timed relation with the cam shaft of the block machine, designated 71, is a device that includes a series of rotary cams which operate switches. designated respectively CLS1, CLS2 and CLS3. The selector switch 67 may be set for automatic operation or hand operation, as indicated, and additionally included in the electric circuit are the push buttons 68 and 69.

At the beginning of each block making cycle the switch CLSl is closed, and with power being supplied to the electric system through a three phase power line, as shown, the coil M of the main drive motor MD is energized, in consequence of which the switch associated with the coil aforesaid, designated SW1, is closed and power is' supplied to the main drive motor MD. Initial operation of this motor is translated into shifting movement of the feed box 10, whereby a chargeof concrete is delivered by the latter to the mold box, designated 72.

When the feed box 10 is fully extended, the switch CLSl opens, and the coil M is deenergized, in consequence of which the switch SW1 opens, whereupon operation of the main drive motor MD is terminated. Simultaneously, with opening of the switch CLS1, the normally open switch CLS2 closes, and the coil FDT of the feed timer 66 is energized, in consequence of which the feed timer 66 operates for a present period of time, after which the normally open feed timer points, designated FDTI, close, in consequence of which power is again supplied to the coil M, whereupon the switch SW1 recloses and power is once more supplied to the main drive motor MD, thus initiating a second period of operation. From the time the main drive motor MD ceases to operate until the time it resumes operation, a period of time in the order of two seconds, the feed box 10 remains over the mold box 72. This time period may be varied, as desired, by an appropriate setting of the feed timer dial.

Resumedoperation of the main drive motor MD is translated into shifting movement of the feed box 10 and lowering of the stripper head, designated 73, whereby the feed'box 10 is retracted to its initial position and the stripper head 73 is lowered to the mouth of the mold box 72. i V

At this point in the operation of the machine, the switch CLS2 reopens, and the coil M is deenergized, in consequence of which the'swi-tch SW1 reopens, whereupon for the second time the operation of the main drive motor. MD. is terminated. Simultaneously, with reopening of the switch CLS2, the normally open switch CLS3 closes, and the coiYFTI of the actual finish time indicator 64 and the coil FT of the desired finish timeindicator 65 are energized, in consequence of which the actual finish time indicator 64 operates untiltheheight.

desired finish time indicator points designated open.

Assuming that the concrete delivered to the mold box 72 by the feed box is not enough and/ or that the delivered concrete lacks sufficient body, i.e., is too soft, for the production of a block of the desired height and density, the height pins 70 will make cont-act prematurely, i.e., before the desired finish time indicator 65- times out, in consequence of which the normally open height pin relay points HP'l' close and the up coil U of the feed control motor FCM is energized, whereupon normally open switch SW2 is closed and the feed control motor FCM is thus supplied with current. This operation of the feed control motor FCM is translated into rotary movement of the cam 48 in a direction for raising the fore end of the feed box 10; Simultaneously with energization of the up coil U of the feed control motor FCM, the time delay relay 'l-Rl is energized. After a predetermined period of time, this time delay relay is automatically deenergized, whereupon the normally closed delay relay points TRl-l open, in' consequence of which the up coil U of the feed control motor FCM is again deenergized, whereupon the switch SW2 reopens and the operation of the feed control motor FCM is terminated. The period of time during which the time delay relay TRl remains energized is just sufiicient for raising the fore end of the feed box 10 a predetermined distance, in the order of one-eighth of an inch.

When the finish time indicator points FT1 open, a second set of finish time indicator points, designated FTZ, close, in consequence of which when the desired finish time indicator 65 is deenergized, the time delay relay TR2 is energized. After a predetermined period of time, the time delay relay TR2 is automatically deenergized, in consequence of which time delay relay points TR2-2 close, whereupon the time delay relay TR3 is energized.

Assuming that the concrete delivered to the mold box 72 by the feed box 10 is too much and/or that the delivered concrete is too dry, i.e., is too stilt for the production of a block of the desired height and density, the height pins 70 will make delayed contact, i.e., after a time delay following deenergization of the time delay relay TR2, while the time delay relay TR3 is energized, in consequence of which the normally closed height pin relay points HPZ open. Before these points open, i.e., during the time delay aforesaid, the down coil D of the feed control motor FCM is energized, whereupon normally open switch SW3 is closed and the feed control motor FCM is thus supplied with current. This operation of the feed control motor FCM is translated into rotary movement of the cam 48 in a direction for lowering the fore end of the feed box 10. When the time delay relay TR3 times out, the time delay relay points TR33 open, in consequence of which the down coil D of the feed control motor FCM is again deenergized, whereupon the switch SW3 reopens and the operation of the feed control motor FCM is terminated. The period of time during which the time delay relay TR3 remains energized is just sufiicient for lowering the fore end of the feed box a predetermined distance, in the order of one-eighth of an inch. It will be understood that auxiliary means (not shown) is provided for closing the height pin circuit in the event that the height pins 70 fail to make contact after the time delay relay TR3 times out.

Assuming that the concrete delivered to the mold box 72 by the feed box 10 is just right in quantity and consistency for the production of a block of the desired height and density, the height pins 70 will make contact while the time delay relay TRZ is energized. In this event,

ages-i321 the electriccircuit to the up coil U will be open at the points FTl, and: the. circuit to the down coil D of the feed box 10 will occur.

When the height pins make contact or the auxiliary means aforesaid operates to close the height pin circuit, the height pin points HP4 close, in consequence of which the coil M of the main drive motor MD is reenergized, whereupon the switch. SW1 is reclosed and power is supplied to the main. drive motor MD, which operates now for stripping the finished block from the mold box 72. It will be understood that the vibrators (not shown) for compacting the fresh concrete, are arranged to operate continuously from the beginning of the block making cycle untilclosing of the height pin circuit.

As indicated hereinbefore, excessive travel of the feed control motor FCM in feed box raising or lowering directions is prevented by the limit switches 61 and 62, operated respectively by the arms 59 and 60, which switches 61 and 62are connected in the electric, circuit, as shown.

When it is desired to change the mode of operation from automatic control to manual control, the selector switch 67 setting is changed from automatic to hand. Then to raise the fore end of the feed box 10, the push button 68 is depressed, in consequence of which the up coil U is energized, whereupon the switch SW2 is closed and the motor FCM is operated in feed box raising direction, and to lower the fore end of the feed box It}, the push button 69 is depressed, in consequence of which the down coil D. is energized, whereupon the switch SW3 is closed and the motor FCM is operated in feed box lowering direction.

When it is desired to raise or lower the fore end of the feed box 10 by hand, the selector switch 67 is set to hand. Then the push button 69 is depressed until the feed box It; is all the way down, i.e., until the low part of the cam 48 is engaged by the roller 49, whereupon the hand lever 52 is swung forwardly about the axis of the rock shaft 36' to Whatever position affords the desired height of the feed box 10 above the mouth of the mold box 72-. The pawl 56' and ratchet plate 54 cooperate to secure the feed box 10 in the position desired. In manipulating the hand lever 52, the operator will be guided bythe scale plate 57, which he will read wit-h the aid of the indicator'58' that; is mounted on the hand lever 52.

Except as indicated hereinbefore, the essential features of construction and operation are the same as those set forth in the copending application hereinabove identified, in consequence of which it is believed that a more detailed description herein is unnecessary to a full understanding of the present invention. Referring particularly to Figure 7, it will be noted, however, that in the improved form of the block making machine, instead of the feed box 10 being extended by the action of an assembly of tension springs, it is extended through the medium of fluid pressure suitably applied to a ram 74.

It will be understood, of course, that the present invention is susceptible of various changes and modifications which may be made from time to time without involving any departure from the general principles or real spirit thereof. Accordingly, it is intended to claim the same broadly as well as specifically, as indicated in the appended claims.

What is claimed as new and useful is:

'1. In combination, an open topped, bottomless feed box for block molding machines for supplying the mold thereof with a determined volume of block molding material, said feed box having at its front end as a fixed part thereof a cut-01f bar of a length sufiicient to transversely span the mold, a stationary apron plate underlying and normally closing said feed box bottom, a pair of laterally spaced parallel rails extending rearwardly from opposite sides of s'aid mold along which the feed, box is adapted to travel during its reciprocation between a box filling station and a mold-char'ging station over the. mold, r'nean's spaced rearwardly of the mold-charging station for pi'votally mounting said rails for tilting movement about a horizontal axis extending transversely of thetline of said reciprocation, and means operativelycoupled to the rails for varying the tilt thereof, whereby upon movement 6f feed box from said mold-charging station to'said box-filling station the volume of the block-molding material constituting the charge for the mold is at a predeterminedly established level not lower than the top of the mold cavity and is variable above the mold top as the elevation of said cut-oif bar is changedin accordance with the tilt of said rails. I

2. A feed box for blocking molding'machines, for charging the mold thereof with a determined, volume of block molding material comprising upright side and end walls and an open top and bottom, a stationary, apron plate underlying and normally closing said feed box bottom, means guiding said box for'substantially hori', zontal reciprocation between a box-filling stationand a mold-charging station over the mold, means mounting said last mentioned means for tilting movement about a horizontal axis extending transversely of the lines of said reciprocation and clemovedtfromsaid mold-charging sta tion, whereby a desired portion of said determined volume is removed from said mold by said box on movement thereof from said mold-charging to said box-filling'station in accordance with the tilt of said guiding-means, said guiding means comprising a pair of rails supporting said feed box for said horizontal reciprocation therealong; and said mounting means comprising'a trunnion mounting at one end of said rails adjacent said box-filling station, a lever cooperating with said rails for eifecting tilting movement thereof about said trunnion mounting, andrmeans for selectively operating said lever to efliect a desired tilt to said rails. V g

3. In a block making machine which operates automatically in repeating block making cycles having a mold, means for charging said mold with a determined volume of block molding material, and means for compacting the material in said mold to form a block and for stripping the block from said mold; the improvement wherein said charging means compris'esa bottomless feed box, a stationary apron plate underlying and normally closing said feed box bottom, means guiding said box for substantially horizontal reciprocation between a box-filling station and a mold-charging station over said mold, means mounting said last mentioned means for tilting movement about a horizontal axis extending transversely of the line of said reciprocation and removed from said charging station, whereby a desired portion of said determined volume is removed from said mold by said box'on movement thereof from said mold-charging to said box-filling station in accordance with the tilt of said guiding means, said guiding means comprising a pair of rails supporting said feed box for said horizontal reciprocation therealong; 'and said mounting means comprising a trunnion mounting at one end of said rails adjacent said box-filling-station, "a lever cooperating with said rails for effecting tilting movement thereof about said trunnion mounting, and means for selectively operating said lever to effect -a desired tilt to said rails. a V

4. In a block making machine as defined in claim 3, means automatically responsive to the time of compacting the material supplied to said mold to a selected dimension compacted to said selected dimension, said apparatus in velectn'cal circuit including means responsive to'the period got ,time ,required :for compacting saidmaterial supplied to said mold for altering the tilt of said rails when said period of time varies from a predetermined period of time, without altering the tilt of said rails when said period of time does not vary from said predetermined period of time. a

6, Ina block making machine as set forth in claim 5 'said apparatus connected in electrical circuit comprising block height determiners including electrical-switch means changed in condition when the material supplied to said mold is compacted to a selected dimension.

7. In. a block molding machine of the type including an open top mold box, an open bottom feed box having a front wall the bottom edge portion of which is adapted to scrape the upper surface of moldable material supplied to said mold box by said feed box and thereby establish the height of the moldable material left in said mold box, feed box support means rockable about a horizontally extending axis disposed to the rear of the mold box, said feed box being mounted upon said support means for horizontal reciprocable movement relative thereto in a line normal to said axis and for, rocking movement about said axis simultaneously with said support means, the fore end of said feed box including companion rollers disposed respectively on opposite sides thereof, the fore end of said support means including a, pair of tracks disposed in underlying relation respectively to said companion rollers, the aft end of said support means including a third roller disposed centrally between the opposite sides of said feed box, the afttend of said feed box including means extending over said third roller' and means adapted to rock said feed box and support means therefor, whereby the front wall of said feed box is raised or lowered to a desired working elevation above said mold box.

8. In a block making machine having a mold box and a side-enclosed bottomless feed box which reciprocates between the mold box and a material supply station disposed rearwardly of the mold box and from which supply station moldable material is supplied to the feed box for delivery to the mold box; the combinationrcomprising a pairrof laterally spaced parallel rails extending rearwardly from opposite sides of said mold box along which the feed box is adapted to travel during its reciprocation between the mold box and the supply station, pivot means displaced rearwardly from the mold box and associated .with said rails for permitting tilting movement of the latter relatively to the horizontal, and lifting means depending from above the mold box and operatively coupled to the rails for lifting the fore ends of the latter and there by tilt the rails about said pivot means to vary the inclination of the feed box in accordance with the tilt of said trails.

9. Ina block making machine having a mold'box and a side-enclosed bottomless feed box which reciprocates .between the mold box and a material supply station disposed rearwardly of the mold box and from which supply station moldablematerial is supplied to the feed box for delivery to the mold box; the combination comprising a placed .rearw-ardly from the mold box and associated with .said rails for permitting tilting movement of the latter relatively to the horizontal, elevating means'operatively coupled to the rails at points spaced from said pivot means and operable from above the mold box to tilt said rails about said pivot means and thereby vary the inclination of the feed box in accordance with the tilt of said rails, a power transmission coupled to said elevating means and operable when actuated to cause said elevating means to change the tilt of said rails and the inclination of the feed box, power transmissioncontrol'means for selectively actuating said power transmission, and means goupling said control 'means to said power transmission. 10. In a block making machine having'a mold box and a side-enclosed bottomless feed box which reciprocates between the mold box and a material supply station disposed rearwardly of the mold box and from which supply station moldable material is supplied to the feed box for delivery to the mold box; the combination comprising a pair of laterally spaced parallel rails extending rearwardly from opposite sides of said mold box along which the feed box is adapted to travel during its reciprocation between the mold box and the supply station, pivot means displaced rearwardly from the mold box and associated with said rails for permitting tilting movement of the latter relatively to the horizontal, elevating means operatively coupled to the rails at points spaced from said pivot means and operable from above the mold box to tilt said rails about said pivot means and thereby vary the inclination of the feed box in accordance with the tilt of said rails, a power transmission coupled to said elevating means and operable when actuated to cause said elevating means to change the tilt of said rails and the inclination of the feed box, power transmission control means for selectively actuating said power transmission, means coupling said control means to said power transmission, and additional means coupled to said elevating means for causing the latter to change the tilt of said rails independently of said power transmission control means.

11. The apparatus according to claim wherein said additional means is manually operable.

12. In a block molding machine of the type including an open top mold box, and an open bottom feed box having a front wall the bottom edge portion of which is adapted to scrape the upper surface of moldable material supplied to said mold box by said feed box and thereby establish the height of the moldable material left in said mold box, the combination comprising; support means rockable about a horizontally extending axis said feed box being mounted upon said means for horizontal reciprocable movement relative thereto in a line normal to said axis and for rocking movement simultaneously with said means, and means adapted to rock said feed box and the mounting means therefor for raising or lowering the front wall of the feed box comprising a rock shaft, articulated means eccentrically connected to said shaft and depending therefrom for connection to the fore end of said feed box mounting means, a cam proximate said shaft, a cam follower eccentrically mounted on said shaft and constantly urged into engagement with said cam by the combined weights of said feed box and the mounting means therefor carried by said articulated means and acting on said shaft, said cam being operable for actuating said follower and rocking said shaft to thereby raise and lower said articulated means and to correspondingly raise and lower the fore end of said feed box mounting means, whereby said feed box and the means for mounting the same are rocked and the fore end of said feed box is raised or lowered to the desired working elevation.

13. In a block molding machine of the type including an open top mold box, and an open bottom feed box having a front wall the bottom edge portion of which is adapted to scrape the upper surface of moldable material supplied to said mold box by said feed box and thereby establish the height of the moldable material left in said mold box, the combination comprising; Support means rockable about a horizontally extending axis, said feed box being mountable upon said means for horizontal reciprocable movement relative thereto in a line normal to said axis and for rocking movement simultaneously with said means, and means adapted to rock said feed box and the mounting means therefor for raising or lowering the front wall of the feed box to a desired working elevation above the mold box comprising a rock shaft, articulated means eccentrically connected to said shaft and depending therefrom for connection to the fore end of said feed box mounting means, means operating to counterbalance a substantial portion of the combined weights of said feed box and the mounting means therefor carried by said articulated means and acting on said shaft, a cam proximate said shaft and having high and low parts, a cam follower eccentrically mounted on said shaft and constantly urged into engagement with said cam by the unbalanced portion of the combined weights aforesaid, power means for turning said cam to a position wherein said cam follower engages the low part thereof and the front wall of said feed box is lowered, and a lever fixed to said shaft and manually operable for rocking the same in a direction for disengaging said cam follower from said cam and for raising the front wall of said feed box.

14. In a block molding machine of the type including an open top mold box, and an open bottom feed box having a front wall the bottom edge portion of which is adapted to scrape the upper surface of moldable material supplied to said mold box by said feed box and thereby establish the height of the moldable material left in said mold box, the combination comprising; support means rockable about a horizontally extending axis, said feed box being mounted upon said means for horizontal reciprocable movement relative thereto in a line normal to said axis and for rocking movement simultaneously with said means, and means adapted to rock said feed box and the mounting means therefor for raising or lowering the front wall of the feed box to a desired working elevation above the mold box comprising a rock shaft, articulated means eccentrically connected to said shaft and depending therefrom for connection to the fore end of said feed box mounting means, a cam proximate said shaft and having high and low parts, a cam follower eccentrically mounted on said shaft and constantly urged into engagement with said cam by the combined weights of said feed box and the mounting means therefor carried by said articulated means and acting on said shaft, power means for turning said cam to a position wherein said cam follower engages the low part thereof and the front wall of said feed box is lowered, means fixed to said shaft and manually operable for rocking the same in a direction for disengaging said cam follower from said cam and for raising the front wall of said feed box, and means for releasably automatically securing said manually operable shaft rocking means in a selected position.

References Cited in the file of this patent UNITED STATES PATENTS 1,268,226 Flood June 4, 1918 2,672,669 Davis Mar. 23, 1954 2,685,116 Schutt Aug. 3, 1954 2,686,950 Zevely Aug. 24, 1954 FOREIGN PATENTS 445,014 Great Britain Apr. 1, 1936 588,856 Great Britain June 4, 1947 

